Oddly enough, my parents have only just got rid of their wooden extension ladders, which they've had since around 1980. When they originally got them, they cost a fiver from British Rail. It seems that BR bought a load of them for their overhead line maintenance crews, but the unions rejected them, insisting that aluminium ones had to be used! I must admit that we had to cut them down by half a dozen rungs to get them into the garage and even then, they were so heavy that you had to have two people to erect them safely. They are the only wooden ladders that I have ever used that were virtually as bounce free as an aluminum set, but totally impractical due to the weight.
SteveW